SMTP Errors - Undeliverable emails

[nifita]

A number of users here are getting failures sending email with varying messages. It seems random, sometimes it sends to the address, sometime it fails with the same address.
Here are four of the messages:
There was a SMTP communication problem with the recipient's email server. 553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)

There was a SMTP communication problem with the recipient's email server. 550 not local host genericcompany.com, not a gateway

You do not have permission to send to this recipient. 550 5.7.1 ... SMTP relay denied, authenticate via POP/IMAP first

You do not have permission to send to this recipient. 550 5.7.1 Unable to relay for user@mail.com

You do not have permission to send to this recipient. 550 5.7.1 <user@mail.com>... Relaying denied, Did you pop before sending?>

Can anyone clue me in as to what's going on? Running Win2003 server with Exchange 2003 and IIS 6.0. Clients are Outlook 2002 on WinNT 4.0 and Win2000 Pro.

Thanks for any help!

 

[KellieK97]

I have the EXACT same problem....someone please help

 

[nifita]

KellieK97, I did find out that my issue seemed to be related to Symantec Mail Security for Microsoft Exchange that I had installed recently. It has a Temp folder that was being scanned by Symantec Antivirus, so I just had to exclude that folder from the scan (got the solution from Symantec Tech Support). If you have that software, that may be your answer. Otherwise, I'm not sure.
Good luck and HTH!

 

[Adr3nalin]

Probably this is related to DNS REVERSE LOOKUP policy in recipient mail server. They won't accept email from senders mail server that does not have ip address reverse lookup.

if this is the case: please check and acquire this from your ISP.

 

[AndyPeck]

Guys

I've seen a Similar problem before that only effected mail destined for companies with large number of records, in fact only email to hp.com & ibm.com was being affected. (That we found)

An nslookup would fail to retrieve the information for these domains, but any other domain we could think of worked ok.

Turned out that the PIX firewall that sits on the border has DNS fixup enabled, which restricts the size of DNS packets to 512 bytes, so it was dropping the replies for these large domains.

Just thought I drop that into the pot, as we were quite sure it was a reverse DNS issue for some time due to the symptoms.


Hope this helps


Andy Peck

 

[KellieK97]

Everyone,

We had our ISP do the DNS reverse lookup and that didn't seem to help. I also looked on our 3Com Firewall and there doesn't seem to be anywhere where you can set the size of the DNS packets. I am at a loss as to why it only happens to certain people. It has not once happened to my PC and I'm the only one running 2000, everyone else is running XP. I doubt that this would matter, but I have no idea what the issue seems to be. Hopefully this problem can be resolved soon....I'm going crazy. Anyone have any other thoughts

Thanks,

Kellie

 

[pschwarz]

Make sure that you have a good antivirus engine and that it is properly configured (for exchange and pattern updates). Some of the newer viruses give NDR error messages (W32.Netsky.P@mm is one example... which just came out 3/21). Make sure that you are not an open relay (

http://www.spammarshall.com).

Can't remember how I did it off the top of my head, but setup exchange to deliver all NDR's to you, as well as your users. This will help to track all of them (whether they are immediate, or timing out after a period of time).